1. Field of the Invention
This invention relates to a vehicle field and, more particularly, to a rear axle differential device of a vehicle.
2. Description of the Related Art
A differential gear is a main part of a drive axle and is used for allowing half-shafts at two sides to rotate at different speeds when transmitting power to the half-shafts at two sides, to satisfy unequal-distance drive of two wheels in a pure-rolling mode, thereby reducing friction between tires and the ground. Therefore, the characteristic that the two wheels at two sides of the drive axle of a vehicle rotate at different speeds when the routes are not equal can be ensured, further to satisfy requirements of vehicle kinesiology.
At present, most vehicles are two-wheel drive vehicles, such as front-wheel drive vehicles or rear-wheel drive vehicles. Therefore, conventional engines mostly match the two-wheel drive vehicles. However, since all-terrain vehicles used outdoors, such as off-road vehicles and utility vehicles, need good cross-country performance (such as grade climbing or wading), and the common two-wheel drive vehicles are easy to skid, the all-terrain vehicles, such as the off-road vehicles and the utility vehicles, are usually set to be four-wheel drive.
Since the present two-wheel drive mostly adopts a front-wheel drive layout, and the engine is disposed in the front part of the vehicle and is connected with a front axle. However, in a four-wheel drive all-terrain vehicle, the engine needs to be connected with a rear axle. At present, the engines on the market cannot match the rear axle of the all-terrain vehicle. If a mold is made again specially for producing the engines, a long research and development period is needed and the research and development costs are high.